Telephone system.



G. A. BETULANDBR. TELEPHONE SYSTEM.

APPLIOATION HLED'NOV. z2. 1910.

1,070,104. Patented Aug. 12,1913.

ifi in sans ernten TELEPHONE SYSTEM.

Specification of Letters Patent.

Application lecl November 22, 1910.

Serial No. 593,668.

To all 'whom t may concern."

Be it known that I, Gor'rHILr ANSGA'RIUS VBETULArunen, a subject of the Kingdom oit Sweden, and resident of Saltsj-Nacka, in the Kingdom of Sweden, have invented certain new and useful Improvements in rFelephone Systems, of which the following is a speciiication, reference being had therein to the accompanying drawing.

rlhe present invention has for its object to prevent loss of current caused by leakage especially in sources of galvanic current,- which deliver current periodically only to lines in which leakage may occur. Such loss of current may occur for instance, by earth leakage in lines carried in the open air, in automatic telephone systems, the currents necessary for the automatic connection being sent out from an earthed battery through the said lines, periodically and during short periods only. rThe battery being generally connected constantly to the line at the centrail-station it will send out a useless current,

it leakage should occur on the line, which current may damage the battery and disturb the connecting operation. According to this `invention, the said disadvantage is overcome by the battery being normally separated from the line and, as occasion requires, connected to the sameA through a relay which cuts in simultaneously a time switch adapted to disconnect the battery from the line after 'a certain period. The said relay, when being traversed by a current suitably puts itself into a holding circuit containing the said time switch. f lhus, the battery-remains connected to the line as longas the holding circuit is closed, z'. e. during that period at most in which the time switch is adjusted to operate. if `a longer impulse of current is to be sent through the line, the holding circuit may be led through the said yline, the holding current formin the said impulse of current. 'F or producing an impulse of current through therelayv cutting in the battery an auxiliary relay may suitably be used which is actuated by means of an alternating current and closes a circuit for a moment lthrough the relay rst mentioned, whereby the same connects the battery with the line and puts itself into the holding circuit containing the time switch.

The annexed drawing shows the said invention as applied t0 an automatic telephone 'tro-magnet 11, whose armature 33,

`sub-station each line branch, 1 and 2, in-

cludes a switch 3, 4, contacts 5, 6, being provided for connecting the said switches with earth. @ne switch, 3, is used for establish-y ing the desired connections and the other switch, d, tor disconnection.

The connecting apparatus connected with thesubscribers telephone apparatus comprises a connect-ing electro-magnet, 9, a disconnecting electro-magnet, 10, a locking elecnormally prevents the armature 22 ci" the connecting electro-magnet trom being attracted by the latter, and a cut-out V'electro-magnet 12, which by attracting the armature 37, carr ing the two movable line contacts or springs l15,5, 18, during 'the connecting operation, prevents the said line-contacts from making contact with connecting wires leading to the connecting apparatus of subscribersv with which no connection is desired. @t the two line branches 1, 2, 1 is connected with -a relay 71, as also through a wire 13, with one of the connecting springs 15, and the other line branch 2 is connected with another relay 72, as also through a wire 141, with the other connecting spring 16. rlhe windings ot the relays are connected together, and further, each of the said windings is connected by wires 89, 83, with the armatures 79, 80, of the relays, 71 and 72 respectively, the stationary contacts 75, 76, of which are con' nected together by a wire 78, connected with the magnet 11, by a wire 90., 'lhe said relays 71,`72, have two additional contacts 73, 74, coperating with two armatures 81 and 82, respectively connected to eartlnl The windings of the connecting electromagnet 9, and disconnecting electro-magnet 10 are connected together by a wire 17, and with the contacts 73, 74 respectively. iThe wire 17 is connected by a wire 24:, including a time-lag contact or time switch 77, with the wire 26, leading from the connecting battery 27. Further, a relay 84 is provided between racenteuanggiaiaia. i

ytioned, the object of which x ergized and its armature 23 the line branches l, 2, a condenser being connected in series with the said relay. rllhe stationary contact 86 of the relay 84 is connected with the wire 7 8 at the contact 76. rlhe armature S7 of the said relay is connected'with the wire 83. rlhe relay last menis to cause the niagnetizing of the relays 7l, 72, when calling by means of induced current, may be dispensed with, it' the armatures of the relays 7l, 72, are made sufficiently sensitive.

rlhe armature 22 of the connecting electromagnet 9 is provided with a :tee'ing arm.l

23, which by means ot a tooth or the like ei'w'agesy the teeth ot a connecting bar 29 or any other movable part, carrying the connectingsprings lo, i6, connected with the line branches respectively, while the arma.

-ture 23 of the disconnecting electro-magnet l() is provided with a locking pawl 30, which, as the disconnecting electro-magnet is enis attracted, enthe movable part 29 and part falling. l/l] hen the electro-magnets A9, 10, become denergized, their armatures 22, 23, are moved to their normal positions shown in 'the drawing.

ln order to prevent too great a load on the connecting battery 27 and yexhausting it by leakage on the line or for any other reason, the time lag contact 77 is provided in the wire '2G between the battery 27 and the magnets l2, ll and 9, l() respectively, which, for instance, is controlled by a cloclrworlr, disengaged by an electromagnet 38, the mechanism being so adapted that the Contact 77 will be broken, o-nly'it a current passes through the wire 26 during a period which is somewhat llonger than that required for the connecting operation, the contact being then immediately again closed.

Suppose the subscriber at substation il wishes to put hiniselt in communication with substation lll., lle then closes the earth contact 5 for instance athis telephone appa ratus l and rotates the armature ot the magneto-generator 7 ot said apparatus, whereby an alternating current passes through the relay 3d, which attracts its armature 37, the following circuit being thereby established; earth, battery v27, wire 26, time-lag contact 77,'electromagnets 12 and il', wire 90, wire 7 3, contact 86, armature 87 and then partly gages the teeth ot prevents the said through relay l partly through relay 72,

line branches 1,. 2, contacts 3, d, contact 5 and earth. @wing to the-said circuit the contacts 73, 75, 76, 74C are closed and are held in their closed positions, as the current now passes through the wire 33, to the relays 7l, 72, At the saine time the current from the wire 2G through the wires 2t, 17, is divided into two parallel branches, comprising the connecting and disconnecting electro-- magnets 9 and l0 respectively, contacts 73, 7e respectively and earth, As the electro- `idownward. By closing nordica magnet ll now attractsits armature 33, the armature 22 of the connecting electromaE net-9 is freed and is attracted by the said magnet 9. @n account of the elcctromagnets 9, 10, having attracted their armatures, the toothr of the feeding arm 28 has passed the uppermost tooth of the bar 29 and entered into the notch beneath the said tooth, while the pawl 30 engages and holds the bar., 'llhe lower end of the feeding arm 28 has now passed the top end of the armature 23the top end of which, consequently, enters the space between the bar 29 and the feeding arm., llt now, the connecting switch 3 ot the substation ll" is forced downward, the current from the battery 27 ceases to dow through the relay 71,'the armatures 7 9 and 8l are released and the current through the connecting electro-magnet 9 is broken at 73, so that the armature 22 and the feeding arm 28, acted upon by the spring 3l, raises the bar 29 a distance corresponding to the length of a tooth, which is equal to the distance between the connecting wires.

Ars the'bar 29 is raised the end of the pawl i 30slips over a tooth of the bar and enters the notch nearest below that tooth, thus holding the bar in its raised position, in case the connecting switch 3 should again close the circuit through the electro-magnet 9,

ln order that the calling subscriber may be able to bring the contact springs l5, 1G, ot his connecting apparatus d. into contact with the Contact wires 104, 114i-, ot the apparatus of the subscriber, with which kconnection is desired, the bar 29 must be moved -tour steps according to the drawing. llt tollows from the preceding that, for this purpose, tour interruptions must be made by means of the switchk 3.. The earth contacts 5, G, are then broken beiore the switch 3 is allowed to return after the fourth interrup tion. 0n account of the break at the earth contacts 5, 6, the battery 27 ceases to supply current and the armature 23 with its pawl 30 is retracted by the spring 32, so that the pawl 30 is brought out of engagement with the bar 29 which is now kept in its raised position only by the feeding arm 2S.

l/V hen it is desired, after conversation has been finished, toy restore the connecting apparatus to' its normal or resting position, the same operations`are made as in establishing the desired connection, only with the diEerf ence that, instead of breaking` the switch 3, the disconnecting switch 4: is Irnow forced the earth contact 5 and rotating the magneto-generator 7 of the telephone apparatus, the electrofmagnets 9 and l0 are caused, as the action of the relays 84, 71, 72, to attract their armatures 22, 23, respectively, and the lower end of the arm 23 then, as before, passes the top end ,of the armature 23, By forcing 'the disconnecting switch e downbefore described, by

ward, an interruption by the action of the electro-magnet 72 is made in that branch of the circuit of battery 27 comprising the disconnecting electro-magnet 10, and the armature 23 is thus retracted by its spring 32, but as the top end of the armature 23 projects between the bar 29 and the arm 28 the latter is caused to follow, Vso that the tooth of the said arm is brought out of engage-,1l ment with the bar, which is brought back by c its own weight or by any other force into its normal position, Before the disconnecting switch 4 is allowed to return upward, the earth contacts 5, 6 are broken, whereby the branch of the circuit of battery 27 comprising the electro-magnet 9 is also broken. The armature 22 is then retracted by its spring 31 and pulls the arm 28 upward, and when the top end of the armature 23 releases the end of the arm 28, the latter enters into and engages the uppermost notch of the bar 29.

If now, for instance, an earth leakage should occur in the line branch 1, the relay 71 will be traversed by a current even after the connecting period has finished, and then the contact 77 is broken after a certain period.

Thereby the relay 71 becomes currentless and releases its armature, so that the battery, notwithstanding the following closing of contact 77, cannot again be connected to the line before the next ,connecting operation. In case of earth leakage in the line branch 2 the relay 72 also remains currentcarrying through the armature 80 until the current is broken at, the contact 77. In the indicated example of connection a greater leakage in the branch 2 would also render the connection quite impossible. In the drawing each connecting apparatus is provided with a time switch 77 but, of course,

a single switch may be used for sets of connecting apparatus or for the whole exchange.

at I claim is:

1. In safety devices for preventing loss of current by leakage the combination with a source of current and a line normally separated frolnthe said source of current, of a relay, adapted to effect the connection of the said line with the source of current and a time switch adapted to disconnect the source o f urr'ent from the line after a certain perio 2. In safety devices for preventing loss of current by leakage the combination with a source of current and a line normally separated from the said source of current, of a relay adapted to effect the connection of the said line with the source of currentk and a holding' circuit for the said relay including a time switch.

3. In safety devices for preventingr loss of current '-by leakage the combination with a source of current and a line normally separated from the said source of current, of a relay adapted to effect the connection of the said line with the source of current, and a time switch adapted to disconnect the source of current from the` line after a certain period, an auxiliary relay and an auxiliary circuit including the relay first mentioned and a contact device operated by the auxiliary relay to close the auxiliary circuit.

In witness whereof, I x have hereunto signed my name in the presence of two subscribing witnesses.

GOTTHILF ANSGARIUS BETULANDER.

Witnesses:

OSCAR GRAHN, THowALD N YsTRoM. 

